California Insurance Commissioner Dave Jones is asking insurance companies writing more than $100 million in premiums to respond to a climate change survey.

The move doubles the number of companies required to tell regulators the financial risks they face from climate change and the actions they’re taking to respond.

Jones says the survey allows regulators to identify vulnerabilities and best practices by insurance companies.

"They are exposed to potentially increasing levels of loss," says Jones. "What the survey does is simply ask them what they are doing with regard to their underwriting practices, their investment portfolio and their business operations.”

Since 2009, the National Association of Insurance Commissioners has prepared the survey and suggested that commissioners survey companies doing business in their states. Compliance is voluntary. So far, only five states have complied. They represent about 77 percent of the insurance market.

*this article was corrected to clarify that compliance is voluntary, not mandatory.